High purity phosphorus oxychloride (99.9999%-99.99999%) is one of the key basic chemical materials in manufacturing process of solar cell, and is mainly used in N type doping of solar cell; its purity and cleanliness have great influence on finished product rate, electrical performance and reliability of solar cell, but it is a colorless transparent chemical material with strong corrosivity, oxidability, high toxicity, and violent reactivity with water. Chinese patent CN202546241U discloses a high-purity phosphorus oxychloride safety feeding device, wherein its structure is: a high-purity phosphorus oxychloride storage tank in a thermostat is connected with a nitrogen inlet pipe and a nitrogen outlet pipe, and a temperature digital display meter is provided on the thermostat; one end of the nitrogen inlet pipe is inserted into the bottom part of the high-purity phosphorus oxychloride storage tank, and the other end thereof is connected with a nitrogen valve. The system completely avoids the explosion risk generated when the high-purity phosphorus oxychloride meets water, improves safety of the high-purity phosphorus oxychloride in use and reduces the production and maintenance costs of the phosphorus oxychloride user and the logistics cost of the high-purity phosphorus oxychloride supplier; however, the shortcomings of the system are as below: it can not carry out the remote monitoring on the using site of the high-purity phosphorus oxychloride and the accurate monitoring of material liquid level; cannot timely alarm and handle when the high-purity phosphorus oxychloride is leaked; cannot process the nitrogen pressure release problem caused by a man-made maloperation (the air outlet valve is not opened when opening the nitrogen gas valve); therefore, the system has various hidden troubles in production safety; its production safety and working efficiency are low.